Association of heat shock factor protein 1 and prolactin receptor variants with molecular breeding values in Senepol cattle

Thermal stress has been associated with lower food intake and growth rate in beef cattle. The purpose of this study was to assess the segregation of the p.Leu462· nonsense mutation in the prolactin receptor gene (PRLR) responsible for slick hair (SH) phenotype in Senepol and a T >C missense variant (V344A) located in the heat shock transcription factor protein 1 gene (HSF1). We compared the potential association of these polymorphisms with molecular breeding values (MBV) that were estimated using a panel of commercial genetic markers (Igenity, Neogen Corp). For this, 29 females and 21 males were genotyped by PCR and sequencing. Three genotypes were observed for the p.Leu462· with frequencies of 0.02 C/C, 0.16 C/- and 0.82 -/-. For V344A only two genotypes were observed with frequencies of 0.86/TT and 0.14/TC This polymorphism was in linkage disequilibrium with a C >T synonymous variant; therefore, for the statistical analyses, the HSF1 genotypes were combined as TT/CC and TC/CT. The GLIMMIX procedure and Tukey test of SAS were used (effect of sex, HSF1 and SH genotype and interactions). MBV for production traits such as average daily gain, tenderness, yearling weight (YW), marbling, fat thickness (FT), percent choice (PC), ribeye area (RA) and carcass weight. Effect of sex (P < .05) were found for YW (males: 6.93lbs ± 0.53, female: 5.74lbs ± 0.57) and for PC (female: 16.17±0.75, male: 15.02±0.55). Differences between HSF1 genotype combinations were significant for the MBV of RA (TC/CT: 0.96in2±0.10; TT/CC: 0.781in2±0.07 and for FT (TC/CT: 0.16in±0.02; TTCC: 0.12in±0.01). The similarity in segregation of SH responsible genotypes (C/- and -/-) and HSF1 (TC/CT and TT/CC) in Senepol could indicate a potential role of HSF1 in adaptation to heat stress in cattle with an additional effect in muscling and fat deposition.